80 Series Locker Computer

[EricG]

Hi Guys,
I'm trying to figure out why my rear locker doesn't work. I've found that the relay behind the passenger kick panel isn't clicking for the rear locker, like it does for the front one. The relays are all on a circuit board in a black box directly behind the kick panel.

So I'd like to figure out if it's the control board itself, or somewhere else in the wiring. Does anybody have a spare one I could try? Or willing to pull theirs and let me try it? Takes about 5 minutes with a 10mm socket.

Thanks!

 

[CO_Hunter]

Eric,

I thought I had an electrical problem with my front last year. Turned out to be that water had gotten into the housing and corroded things not making good contact. If the contacts are gummed up the electric circuit may not be closed, as in my case. That is the most likely culprit as I understand the ECU's are quite dependable. My relay would actually chatter a bit. I thought it was bad but turns out it was low voltage causing the chatter.

If it does turn out to be a relay a guy on MUD has a source, that is how I tracked down my real problem.

 

[EricG]

So when that happened, would the relay behind the panel still click? That's why I've focused there to start, but if a problem at the actuator can cause the relay to not click, I'll start down there. I've heard that the ECU is very reliable also, but mechanical relays do go bad sometimes.

I did have the rear locker actuator apart about a year ago, but in that case it was the shaft that was sticking. The motor still ran fine. The motor is definitely not running now. I wanted to check voltages at the actuator, but can't get the damn connector apart.

 

[CO_Hunter]

If there is a bad or no electrical connection in the actuator there is not enough voltage or current to throw the relay. Those connectors were a pain in the butt for me as well.

Here is a link to my locker thread, it also has part numbers if you need them but remember mine is a '96.

https://forum.ih8mud.com/80-series-tech/408534-bad-locker-ecu-relays-replaceable.html

 

[black95]

Since it only works half the time, just put an ARB sticker on it and it will seem normal...

 

[EricG]

If there is a bad or no electrical connection in the actuator there is not enough voltage or current to throw the relay. Those connectors were a pain in the butt for me as well.

Here is a link to my locker thread, it also has part numbers if you need them but remember mine is a '96.

https://forum.ih8mud.com/80-series-tech/408534-bad-locker-ecu-relays-replaceable.html

Thanks for the link - looks like it could be in the actuator, based on Tools R Us's comment:

The ground that triggers/holds the relay closed comes from the position/wiper switch in the actuator.

I'll be kind of surprised, since I cleaned and sealed that whole business a year ago, but I haven't found a way to test the relays on the ECU independently yet. Guess I'll fight with that connection again. I made a point of lubricating it last time, but it's still stubborn.

I've also noticed a relay chattering from behind that kick panel sometimes when I first start the truck. Which is odd, since I'm not in low range and don't have the lockers engaged??

 

[EricG]

Pulled the actuator today, and it somehow got wet inside again - all crapped up. The motor runs fine, so I'll clean it up and try again. Not sure how it got wet in there - it was all sealed up with FIPG, and I've never had it deep enough to submerge the actuator anyway.

 

[CO_Hunter]

Cracked or disconnected vent tube?

 

[EricG]

Cracked or disconnected vent tube?

Vent tube was connected, and intact for the first inch or so before it was wrapped up with the harness. I'll take a closer look at it when I put it back together.

 

[EricG]

Well, cleaned, lubed & re-assembled it today. Now the relay clicks and the servo runs ... but still no lock. Light stays flashing and it doesn't feel locked when turning. Did lots of turns.

So, I'm thinking either the clockwork mechanism is frozen ... probably should have put it in a vice and tried it. Or I somehow put it back together wrong such that everything is working, except the push rod doesn't have the right travel to make it engage. Guess I'll be taking it apart again

I think the water got in through that front cover plate - there was an area in the o-ring groove that was corroded, and the RTV in the groove kind of crumbled. May be because I didn't know how to use RTV right. The instructions on this one say to assemble finger-tight, let it dry, and then tighten it. Didn't do that last time, just cranked it tight right away..

 

[CO_Hunter]

It's been a while since I had the rear apart but I recall the rear being a bit tricky to re-install. When I was testing mine I had one rear wheel off the ground with the switch turned on. All I had to do was rotate the wheel a small amount and I could hear it lock.

When I put the RTV on the front of mine I did it the way you did but I kept the old O ring in there

 

[EricG]

It's been a while since I had the rear apart but I recall the rear being a bit tricky to re-install. When I was testing mine I had one rear wheel off the ground with the switch turned on. All I had to do was rotate the wheel a small amount and I could hear it lock.

When I put the RTV on the front of mine I did it the way you did but I kept the old O ring in there

Yea, my o-ring was trashed when I took it apart the first time. Fell apart.

 

[EricG]

It's working!
The picture below shows the correct orientation of the rear difflock actuator internals when the locker is disengaged. Basically, you pull the shift fork all the way to the left, then line up the actuator shaft and put in the bolt. Then put the clockwork mechanism in, oriented as shown.

What's odd is that I had a picture from when I took this apart in 2008 which I thought showed the correct orientation. So I didn't note it this time. My earlier picture was incorrect somehow.

 

[CO_Hunter]

Glad you got it going!